# CD38 expression

Source: https://onco.cc/biomarkers/cd38-expression/  
OnCo record `cd38-expression` (Biomarker). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

CD38 is on almost every myeloma cell, so daratumumab and isatuximab are given without testing for it. The stain matters afterwards: CD38 falls after treatment and can confuse flow cytometry and blood typing.

## Summary

Daratumumab and isatuximab are CD38-directed antibodies labelled for multiple myeloma by line of therapy, not by CD38 level; every label describes the antigen only in the mechanism section. CD38 expression is near-universal on plasma cells and drops for months after anti-CD38 therapy, which is why laboratories use alternative gating in flow cytometry and why the drugs interfere with indirect antiglobulin tests.

## Fields

- Kind: Biomarker
- Last checked: 2026-09-23
- Also known as: CD38; CD38-positive; CD38 expression myeloma
- Tags: biomarker; surface-antigen; no-threshold

## Notes

- Lymphoma: there is no approved anti-CD38 indication in lymphoma. CD38 is expressed on a minority of T-cell and NK-cell lymphomas and on plasmablastic tumours, and the evidence there is case series and small trials rather than randomised data. The result that matters in practice is a laboratory one: an anti-CD38 antibody binds CD38 on red cells and makes the indirect antiglobulin test positive, masking genuine alloantibodies, so the transfusion laboratory must be told before a crossmatch.

## Sources

- DARZALEX prescribing information (DailyMed): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a4d0efe9-5e54-467e-9eb4-56fa7d53b60b

## Connected records

- biomarkers: [BCMA expression](https://onco.cc/biomarkers/bcma-expression/), [GPRC5D expression](https://onco.cc/biomarkers/gprc5d-expression/)
- cancers: [Multiple myeloma](https://onco.cc/cancers/multiple-myeloma/), [Newly diagnosed multiple myeloma, transplant-eligible](https://onco.cc/cancers/myeloma-transplant-eligible/), [Newly diagnosed multiple myeloma, transplant-ineligible](https://onco.cc/cancers/myeloma-transplant-ineligible/), [Non-Hodgkin lymphoma (all types)](https://onco.cc/cancers/non-hodgkin-lymphoma/), [Peripheral T-cell lymphomas (including cutaneous T-cell lymphoma)](https://onco.cc/cancers/peripheral-t-cell-lymphoma/), [Relapsed or refractory multiple myeloma](https://onco.cc/cancers/myeloma-relapsed-refractory/)
- drugs: [Daratumumab](https://onco.cc/drugs/daratumumab/), [Isatuximab](https://onco.cc/drugs/isatuximab/)
- terms: [Flow cytometry (immunophenotyping)](https://onco.cc/terms/flow-cytometry/)
- targets: [CD38](https://onco.cc/targets/cd38/)

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